Recently, technology for writing tracks in a magnetic disk with high density has been developed. One of the technology is, for example, shingled write recording technology that partially overlaps and writes data to tracks. By using the shingled write recording technology, the tracks can be written with high density and a storage capacity can be increased.
According to the shingled write recording technology, in the adjacent recording regions of a first track and a second track which is partially overlapped and written to the first track, for example, When a positioning error of the first track occurs in a second track direction and/or When a positioning error of the second track occurs in the first track direction, the width of the first track is narrowed. When an amount of narrowing is great, data written in the first track may be overwritten or destroyed by data of the second track at the narrow portion.
When the data written in the first track is possibly overwritten or destroyed, write inhibit is determined and data writing is stopped. In this case, the write operation is restarted from a position where the writing has been stopped, after awaiting a magnetic disk making one round.
A positioning error of the head is detected at servo sector intervals and actual write inhibit is delayed from a detection of a current positioning error. Therefore, the currently written data may destroy the already written adjacent data in part, in the write inhibit determination based on the positioning error detected with a current servo sector. Since track pitch in an HDD of the shingled write recording technology can be narrowed as compared with that in an HDD of a conventional system, improvement in surface recording density can be realized. For this reason, write inhibit determination based on detection of drift-off (occurrence of positioning error exceeding a specific permissible value), in the HDD of the shingled write recording technology, is of higher importance of as compared with the HDD of the conventional system.